Lithography is a planographic printmaking process based on the immiscibility of oil and water. Traditional lithography is etching on limestone. It takes time and skills (and muscles). There are many quicker versions based on the same principals as with acid and limestone. They are often described as kitchen-litho or paper-litho. I often search for techniques that can be used with kids. You do not get that many editions, but kids dont bother making editions anyway. There can be no dangerous ingredients and it must be quick to learn. But of course, nothing is more juicy than the marks on a fresh stone..